Apparatus and methods for separating blood components

ABSTRACT

Apparatus and methods for separating blood components are disclosed in which an apparatus for separating blood generally includes a tube defining a channel and configured for receiving a quantity of blood and a float contained within the tube and having a density which is predefined so that the float is maintained at equilibrium between a first layer formed from a first fractional component of the blood and a second layer formed from a second fractional component of the blood. Upon completion of the centrifugation, the first layer may be removed from the tube while the float isolates the second layer from the first layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.16/454,525 filed Jun. 27, 2019 which claims the benefit of priority toU.S. Prov. 62/695,631 filed Jul. 9, 2018, each of which is incorporatedherein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present invention relates to apparatus and methods for separatingblood components. More particularly, the present invention relates toapparatus and methods for effectively separating and removing specificcomponents from blood.

BACKGROUND

Blood may be fractionated and the different fractions of the blood usedfor different medical needs. For instance, anemia (low erythrocytelevels) may be treated with infusions of erythrocytes. Thrombocytopenia(low thrombocyte (platelet) levels) may be treated with infusions ofplatelet concentrate.

The sedimentation of the various blood cells and plasma is based on thedifferent specific gravity of the cells and the viscosity of the medium.When sedimented to equilibrium, the component with the highest specificgravity (density) eventually sediments to the bottom, and the lightestrises to the top. Under the influence of gravity or centrifugal force,blood spontaneously sediments into three layers. At equilibrium the top,low-density layer is a straw-colored clear fluid called plasma. Plasmais a water solution of salts, metabolites, peptides, and many proteinsranging from small (insulin) to very large (complement components).Plasma per se has limited use in medicine but may be furtherfractionated to yield proteins used, for instance, to treat hemophilia(factor VIII) or as a hemostatic agent (fibrinogen). The term plateletrich plasma (PRP) is used for this component because most of the plasmaproteins and platelets in the whole blood are in the plasma followingslow centrifugation so the concentration of platelets in the plasma hasincreased while suspended in supernatant plasma. The uppermost layerafter centrifugation typically contains plasma proteins only and istypically called platelet-poor plasma (PPP) due to the absence or lownumber of platelets as a result of a “hard spin”.

The bottom, high-density layer is a deep red viscous fluid comprisingnuclear red blood cells (RBC) specialized for oxygen transport. The redcolor is imparted by a high concentration of chelated iron or heme thatis responsible for the erythrocytes high specific gravity. Packederythrocytes, matched for blood type, are useful for treatment of anemiacaused by, e.g., bleeding. The relative volume of whole blood thatconsists of erythrocytes is called the hematocrit, and in normal humanbeings can range from about 38% to about 54%.

The intermediate layer is the smallest layer, appearing as a thin whiteband on top the erythrocyte layer and below the plasma, and is calledthe buffy coat. The buffy coat itself has two major components,nucleated leukocytes (white blood cells) and a nuclear smaller bodiescalled platelets (or thrombocytes). Leukocytes confer immunity andcontribute to debris scavenging. Platelets seal ruptures in the bloodvessels to stop bleeding and deliver growth and wound healing factors tothe wound site. The buffy coat may be separated from whole blood whenthe blood is subjected to a “hard spin” in which the whole blood is spunhard enough and long enough so that platelets sediment from plasma ontopacked red cells and white cells percolate up through red cell pack tothe interface between red cells and plasma.

When whole blood is centrifuged at a low speed (e.g., up to 1,000 g) fora short time (e.g., two to four minutes) white cells sediment fasterthan red cells and both sediment much faster than platelets. At higherspeeds the same distribution is obtained in a shorter time. The methodof harvesting PRP from whole blood is based on this principle.Centrifugal sedimentation that takes the fractionation only as far asseparation into packed erythrocytes and PRP is called a “soft spin”which is typically used to describe centrifugation conditions underwhich erythrocytes are sedimented but platelets remain in suspension.“Hard spin” is typically used to describe centrifugation conditionsunder which erythrocytes sediment and platelets sediment in a layerimmediately above the layer of erythrocytes.

The auto-transfusion equipment used to make autologous plateletconcentrates requires a skilled operator and considerable time andexpense and these devices require a large prime volume of blood. Whilemany of these devices have somewhat reduced the cost and the timerequired, skilled operators and time are still required. Accordingly,there remains a need for simple and effective methods and devices forseparating and removing components from whole blood. Embodiments of thepresent invention are designed to meet these and other needs.

SUMMARY

Some embodiments of the present invention relate to apparatus andmethods for rapid fractionation of blood into its different components,e.g., erythrocyte, plasma, and platelet fractions. The devices andmethods described have particular value for rapid preparation ofautologous concentrated platelet fractions, e.g., to help or speedhealing.

Whole blood may be spun in a vented tube with a density-adjusted floatmechanism which can float freely and unanchored within the tube alongwith the whole blood. The density of the float mechanism may be adjustedso that when the whole blood has been separated, the float atequilibrium may rest above the sedimented red blood cell (RBC) pack,isolating the PRP supernatant. The float may serve as a barrier toprevent contamination with RBC when the PRP is withdrawn from the tube.

One variation may generally comprise a separator assembly which mayinclude a syringe or centrifuge container tube which defines a channelfor collecting, e.g., a whole blood sample. The separator float may havean atraumatic and arcuate shape, e.g., spherical, ellipsoidal,cylindrical, etc. and having a diameter which corresponds to the innerdiameter of the channel so that the float may move freely within thelength of the channel uninhibited and which allows for blood componentsto pass through the annular space defined between the outer diameter ofthe float and the inner surface of the channel. However, this annularspace may also be small enough so as to discourage the free anduninhibited passage of blood components through.

A float having a spherical shape not only can be used to isolate theupper and lower fluid fractions, but may also decrease the likelihood ofthe float cocking or jamming during centrifugation. Additionally and/oroptionally, select surfaces or all of the surfaces of the float may alsobe optionally treated as well. For instance, overmold skins, siliconecoatings, wetting agents such as latherin, surfactant proteins, etc.,may be applied to the select surfaces of the float or over the entiretyof the float. In one variation, the upper surface of the float may betreated to trap or retain a thin layer of red blood cells upon whichplatelets in the PRP layer may sediment upon. The presence of the redblood cells may cushion and minimize any platelets from directlycontacting the surface of the float which may potential evert and damagethe contacting platelets.

In one variation, the density of the float can be set so that the RBClayer is entirely below the upper surface of the float, e.g., after a“soft spin”. Alternatively, the density of the float may be set tocapture a small amount of the RBC layer above the float. If the buffycoat is desired, the density of the float can be set so that after a“hard spin” the buffy coat and a small amount of the RBC layers areabove the float. The same float may have its density set so that thefloat resides between the RBC layer and the PRP layer, e.g., at itsmidline or anywhere along the float, after a soft spin and then resideswith, e.g., its midline or anywhere along the float, below the buffycoat after a “hard spin”. Some plasma can be withdrawn separately beforethe buffy coat is harvested to produce a more concentrated finalproduct.

As previously mentioned, the float at equilibrium may rest above thesedimented red blood cell (RBC) pack, isolating the PRP supernatant suchas after a “soft spin”. The float at equilibrium may accordinglyseparate the channel between an upper channel in which the PRP layerand/or buffy coat resides above the float (e.g., above the outerdiameter of the float) towards a proximal or proximal or upper end ofthe tube, and a lower channel in which the RBC layer resides below thefloat (e.g., below the outer diameter of the float) towards a distal orlower end of the tube. In other variations, the density of the float maybe tuned so that the buffy coat forms around the periphery of the float,e.g., above the midline of the float or anywhere along the float after a“hard spin”. Separating the PRP layer from the RBC layer helps to ensurethat the any red blood cells from the RBC layer are entirely isolatedfrom the supernatant PRP layer contained above the float.

In another variation the tube may optionally include a seal to maintainsterility. The seal may also incorporate a withdrawal tube connected toa withdrawal tube channel defined through the seal. The position of theseal relative to the tube may be optionally adjusted so that onceprocessing has been completed and the float is positioned at equilibriumrelative to the upper and lower fluid fractions, the seal may be pushed,screwed, or otherwise urged down upon the tube so as to position theopening of the withdrawal tube into contact against or in proximity tothe float so that the PRP layer can be withdrawn through the tube.

In another alternative, the float may optionally incorporate a tetherattached to the float to facilitate its removal, if needed, while inother variations the tether may be configured from a length of tubing,e.g., silicone tubing, connected or connectable to an opening forremoval of the PRP layer. In yet another variation, the relatively highviscosity of the RBC layer may be utilized to maintain separation whenthe tube is inverted so that the supernatant PRP layer can be withdrawnfrom a cap or septum Luer on the top cap of the inverted tube. The tubecould also be configured to expand radially relative to its longitudinalaxis during centrifugation to allow the float to migrate freely withinthe tube to its equilibrium position relative to the centrifugedfractional layers. However, when the centrifugation is stopped, theinner diameter of the tube may contract to trap the float in place atits equilibrium position. The float itself could alternatively becompressible under centrifugally generated pressure but re-expand aftercentrifugation has stopped so as to lock a position of the float againstthe inner surface of the tube at its equilibrium position.

As previously discussed, the float itself may also be in an alternativeshape. Another particular variation of the float may comprise a taperedinterface surface formed in a conical configuration which terminates inan apex that may be atraumatically shaped, e.g., blunted, so as tominimize damage to the blood components. The tapered interface surfacemay be optionally shaped so as to mirror the tapered shape of the tubeinterior. The tapered interface surface may also prevent red blood cellsfrom accumulating upon the upper surface of the float duringcentrifugation. The tapered interface surface may present a slanted ornon-orthogonal surface relative to a normal surface of the float whichmay facilitate the platelets to move or slide down upon the slantedinterface surface. The degree of the slant may range anywhere from,e.g., about 2 to about 45 degrees, although the degree of thenon-orthogonal surface may vary depending on factors such as the volumeof fluid present. Moreover, the surfaces may be smoothed from arelatively rough polymer to a polished surface, e.g., utilizing polymercoatings, nanoparticles, etc. Additionally and/or alternatively, abottom surface of the float may also be tapered as well so as to preventplatelets from depositing upon the lower surface as the red blood cellspack out, squeezing platelets out of the burgeoning pack.

In yet another variation, a syringe or container tube may be used in avacuum-drawn system for separating and then collecting the supernatantfraction. A translatable plunger may be slidably positioned within thechannel and a pull rod may be coupled to the plunger via a plunger lockattached to the plunger on a side of the plunger opposite to the float.A pull rod lock may be integrated with the tube at a distal surface ofthe tube around a pull rod opening through which the pull rod may betranslated. A Luer assembly may be integrated with at a proximal end ofthe tube along with a valve and a cap or septum Luer which may be usedto seal the Luer.

The proximal end of the tube just below the Luer assembly may alsodefine an interface surface which may be tapered or shaped to receivethe float in a corresponding manner to optimize the amount of the PRPlayer which may be withdrawn from the tube.

One variation for utilizing the container tube may utilize the pull rodwhich may be pushed to move the plunger and float into an initialposition where the float is pushed into contact against the interfacesurface of tube prior to receiving whole blood. The tube may be suppliedpreloaded with, e.g., anticoagulant or any other agent, contained withinthe channel. Having the tube preloaded with anticoagulant would enablethe blood to be drawn directly into the tube without the need foradditional processing. With the valve closed, the pull rod may be pulledor pushed to move the plunger into a distal position within the tube.Because the valve is closed, a vacuum may be formed within the tube. Thepull rod may be rotated partially about its longitudinal axis relativeto the tube and plunger so as to lock a position of the pull rod to thetube and to prevent the plunger from being moved back proximally inposition due to the vacuum.

A syringe or blood line may be attached to the Luer and the valve maythen be opened allowing (whole) blood to be drawn through the Luer andinto the channel by the vacuum formed within the tube. Once the bloodhas filled the channel of tube, the valve may then be closed again andthe blood line disconnected and removed. The pull rod may be decoupledor detached from the plunger lock as well as from the pull rod lock suchthat the pull rod is fully removed so that the tube, float, and wholeblood may be centrifuged. With the whole blood introduced within thechannel or tube, the float may remain settled at its distal positionprior to centrifuging the assembly.

Once the tube and its contents have been sufficiently centrifuged, thewhole blood may separate into its fractional components and the floatmay alter its position within the channel accordingly due to thediffering densities of the individual fractional layers. To effectremoval of the PRP layer, a syringe or line may be coupled to the Luerand the valve may then be opened to allow withdrawal of the PRP layerthrough line. The RBC layer may remain between the plunger and float andthe float may remain at the interface of the PRP layer and RBC layer asthe PRP layer is withdrawn through Luer. As the PRP layer is fullywithdrawn the upper surface of the float may come into contact againstthe interface surface of the tube so that the float and interfacesurface form a float interface which may seal the tube and prevent anyfurther withdrawal through Luer. The RBC layer may accordingly remaintrapped between the lower surface of the float and the plunger.

For shipment and storage of the tube, the float may incorporate anattractive element such as a magnet embedded entirely or partiallywithin the float. An externally positioned attractive element may belocated externally of the tube, such as near the bottom of the tube, toattract the embedded element within the float to prevent the float frommovement during shipment or handling of the tube. Prior to use of thetube, the external attractive element may be removed to release aposition of the float within the tube.

In yet another variation, an external clamp on the tube may be used totrap the position of the float at the bottom of the tube to ensure thatthe float remains secured in its position particularly if any preloadedanticoagulant is present within the tube. The clamp may be removedbefore or after blood introduction or before centrifugation.

In one variation, an apparatus for separating blood may generallycomprise a tube defining a channel and configured for receiving aquantity of blood, and a float contained within the tube and having adensity which is predefined so that the float is maintained atequilibrium between a first layer formed from a first fractionalcomponent of the blood and a second layer formed from a secondfractional component of the blood.

In another variation, a method for separating blood may generallycomprise introducing a volume of blood into a channel of a tube whichencloses a float having a density which is predefined, and subjectingthe tube to a centrifugation such that the blood separates into at leasta first layer formed from a first fractional component of the blood anda second layer formed from a second fractional component of the blood,wherein the float is maintained at equilibrium between the first layerand the second layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a perspective of one variation of a float separatorassembly.

FIG. 1B shows a partial cross-sectional side view another variation of afloat separator assembly having a withdrawal tube.

FIGS. 1C and 1D show perspective views of alternative variations forlocking a relative position of the float within the tube aftercentrifugation is completed.

FIGS. 2A and 2B show perspective and side views of another variation ofthe float separator having an upper tapered interface surface and bothupper and lower tapered interface surfaces.

FIG. 3 shows a perspective view of another variation of the floatseparator assembly.

FIGS. 4A to 4G show an example of the float separator assembly used toseparate and selectively collect the different blood components.

FIGS. 5A and 5B show perspective views of the float separator positionedbetween the separated blood components.

FIG. 6 shows a perspective view of a tube assembly which enables thefloat to be maintained in a secured configuration.

FIGS. 7A and 7B show perspective views of the tube with the floatpositioned within the bottom of the tube interior and of the floatremoved from the tube with the attractive element contained entirelywithin or along the float.

FIGS. 8A and 8B show side views of different embodiments of the floatabutting against the bottom of the tube with the attractive elementembedded within the float.

FIG. 9 shows a perspective view of the released float repositioned toseparate the layer of PPP from RBC.

FIG. 10 shows a side view of a tube having a removable packaging postpositioned to secure a position of the float within the tube.

FIG. 11 shows a perspective view of a float maintained in positionwithin the tube via a clamp or other external compressive mechanism.

DETAILED DESCRIPTION

Throughout the description, terms such as “top”, “above, “bottom”,“below” are used to provide context with respect to the relativepositioning of components when, e.g., a container tube with fractionalcomponents of blood are positioned when the longitudinal axis of acontainer tube is positioned upright or non-horizontally. Suchdescription is used for illustrative purposes only.

In one variation of a separator assembly, whole blood may be spun in avented tube with a density-adjusted float mechanism which can floatfreely and unanchored within the tube along with the whole blood. Thedensity of the float mechanism may be defined or predefined usingvarious methodologies, e.g., combining differing polymers in differingratios, integrating weights, removing mass, etc., so that when the wholeblood has been separated, the float at equilibrium may rest above thesedimented red blood cell (RBC) pack, isolating the PRP supernatant. Thefloat may serve as a barrier to prevent contamination with RBC when thePRP is withdrawn from the tube.

One variation is shown in the perspective view of FIG. 1A which shows aseparator assembly 10 which may generally comprise a syringe orcentrifuge container tube 12 which defines a channel 18 for collecting,e.g., a whole blood sample. The container tube 12 may be made of anyvariety of biocompatible materials and may also generally range indimensions but in one example may have an inner diameter of, e.g., 1.5to 3.5 cm, with a length of, e.g., 6 to 12 cm. The separator float 20may have an atraumatic and arcuate shape, e.g., spherical, ellipsoidal,cylindrical, etc. and having a diameter which corresponds to the innerdiameter of the channel 18 so that the float 20 may move freely withinthe length of the channel 18 uninhibited and which allows for bloodcomponents to pass through the annular space defined between the outerdiameter of the float 20 and the inner surface of the channel 18.However, this annular space may also be small enough so as to discouragethe free and uninhibited passage of blood components through. Hence, theouter diameter of the float 20 may range from, e.g., generalized to havean outer diameter of 98 to 101% of the inner surface of the channel 18.

For floats 20 having an outer diameter which equals or exceeds the innerdiameter of the channel 18 in which the float 20 is contained when atrest, such floats 20 may be used with container tubes 12 made fromflexible materials such as plastics or polymers rather than glass. Theinner diameter of the channel 18 may reconfigure itself to radiallyexpand to result in a relatively larger inner diameter, for instance,when spun in a separation procedure. During this spinning process, thefloat 20 may freely move within the channel 18 to a position ofequilibrium relative to the blood components contained within. When thecontainer tube 12 has stopped spinning or has slowed down, the innerdiameter of the channel 18 may reconfigure itself to radially retract toa relatively narrower diameter which may then clamp down or compressagainst the outer diameter of the float 20.

In other variations, the float 20 may have an outer diameter relative tothe inner surface of the channel 18 ranging from tens or hundreds ofmicrons of clearance (or interference), depending on the particularapplication.

The variation shown in FIG. 1A illustrates a float 20 having a sphericalshape which not only can be used to isolate the upper and lower fluidfractions, but may also decrease the likelihood of the float 20 cockingor jamming during centrifugation. The float 20 may also be fabricatedfrom any variety of biocompatible materials so long as the density ofthe float 20 is desirably tuned or tunable for the present application.The float 20 may thus be fabricated as a solid and uniform object(having a suitable density) or in other variations, the float 20 may behollow so as to be injected or filled with a material which allows forthe float 20 density to be changed or desirably adjusted. In thisvariation, the separator float 20 may have a density which is tunedspecifically for use with whole blood, e.g., specific density of 1.0 to1.1 gram/ml at 25° C.), while in other variations, the float 20 may befabricated to have a different density, e.g., 1.03 to 1.07 gram/ml, etc.

Additionally and/or optionally, select surfaces or all of the surfacesof the float 20 may also be optionally treated as well. For instance,overmold skins, silicone coatings, wetting agents such as latherin,surfactant proteins, etc., may be applied to the select surfaces of thefloat or over the entirety of the float. In one variation, the uppersurface of the float 20 may be treated to trap or retain a thin layer ofred blood cells upon which platelets in the PRP layer may sediment upon.The presence of the red blood cells may cushion and isolate anyplatelets from directly contacting the surface of the float 20 which maypotentially evert and damage the contacting platelets. In this instance,at least one layer of the red blood cells upon the surface of the float20 may be sufficient to provide the cushioning to the platelets.

Although the float 20 is shown as having a spherical shape, the floatmay be shaped to have various configurations. For example, in otherembodiments, the float may be shaped to have a cylindrical body having alength and a curved, domed, or otherwise convex shape along the bottomor distal portion of the float. The upper or proximal portion of thefloat may also be curved, domed, convex, concave, or angled relative toa longitudinal axis of the float.

In one variation, the density of the float 20 can be set so that the RBClayer is entirely below the upper surface of the float 20, e.g., after a“soft spin”. Alternatively, the density of the float 20 may be set tocapture a small amount of the RBC layer above the float 20. If the buffycoat is desired, the density of the float 20 can be set so that after a“hard spin” the buffy coat and a small amount of the RBC layers areabove the float 20. The same float 20 may have its density set so thatthe float 20 resides between the RBC layer and the PRP layer, e.g., atits midline or anywhere along the float, after a soft spin and thenresides with, e.g., its midline or anywhere along the float, below thebuffy coat after a “hard spin”. Some plasma can be withdrawn separatelybefore the buffy coat is harvested to produce a more concentrated finalproduct.

For discussion purposes, a “hard spin” may range, e.g., between 2000 to4000×g over 2 to 20 minutes, while a “soft spin” may range, e.g.,between 500 to 1000×g over 5 to 20 minutes.

As previously mentioned, the float 20 at equilibrium may rest above thesedimented red blood cell (RBC) pack, isolating the PRP supernatant suchas after a “soft spin”. The float 20 at equilibrium may accordinglyseparate the channel 18 between an upper channel 22 in which the PRPlayer and/or buffy coat resides above the float 20 (e.g., above theouter diameter of the float 20) towards a proximal or proximal or upperend 14 of the tube 12, and a lower channel 24 in which the RBC layerresides below the float 20 (e.g., below the outer diameter of the float20) towards a distal or lower end 16 of the tube 12. In othervariations, the density of the float 20 may be tuned so that the buffycoat forms around the periphery of the float 20, e.g., above the midline34 of the float 20 after a “hard spin” or anywhere along the float.Separating the PRP layer from the RBC layer helps to ensure that the anyred blood cells from the RBC layer are entirely isolated from thesupernatant PRP layer contained above the float 20. The tube 12 may alsohave a cover or seal and a removable cap or septum Luer 26 through whichthe PRP layer and/or buffy coat may be accessed for removal. While a capmay be removable to provide access for withdrawal, the use of a septumLuer 26 may enable the septum Luer 26 to remain in place, e.g., forintroducing blood into the tube 50.

Alternatively, the tube 12 may be sealed with a conventional septumwhich omits any Luer fittings. By utilizing a septum to seal the tube12, the tube 12 may be vacuum sealed until used.

While the density may be tuned to have the float 20 positioned atequilibrium at specified positions between the fractional layers, thereis relatively greater latitude on the tolerance for the density as thefloat 20. For example, if the float 20 were used to separate theintermediate buffy coat layer after a “hard spin”, the density toleranceon the float 20 would be much tighter given the relatively thin layer ofthe buffy coat compared to the PRP or RBC layers. On the other hand, ifthe float 20 were used to separate the PRP layer from the RBC layerafter a “soft spin”, the latitude on the density range for the float 20would be relatively greater.

Another variation is shown in the partial cross-sectional side view ofFIG. 1B which illustrates a tube 12 having the float 20 within. Anexample of the float neutral line 34 (e.g., outer diameter) is shown forillustrative purposes. The tube 12 may optionally include a seal 28 tomaintain sterility, as described above. The seal 28 may also incorporatea withdrawal tube 30 connected to a withdrawal tube channel 32 definedthrough the seal 28, as illustrated. The position of the seal 28relative to the tube 12 may be optionally adjusted so that onceprocessing has been completed and the float 20 is positioned atequilibrium relative to the upper and lower fluid fractions, the seal 28may be pushed, screwed, or otherwise urged down upon the tube 12 so asto position the opening of the withdrawal tube 30 into contact againstor in proximity to the float 20 so that the PRP layer can be withdrawnthrough the tube 30.

In another alternative, the float 20 may optionally incorporate a tether(not shown) attached to the float 20 to facilitate its removal, ifneeded, while in other variations the tether may be configured from alength of tubing, e.g., silicone tubing, connected or connectable to anopening for removal of the PRP layer. In yet another variation, therelatively high viscosity of the RBC layer may be utilized to maintainseparation when the tube 12 is inverted so that the supernatant PRPlayer can be withdrawn from a cap or septum Luer 26 on the top cap ofthe inverted tube 12. If the viscosity of the RBC layer is insufficientto reliably maintain separation when the tube is inverted, the tube 12could be configured to expand radially relative to its longitudinal axisduring centrifugation to allow the float 20 to migrate freely within thetube 12 to its equilibrium position relative to the centrifugedfractional layers, as illustrated in FIG. 1C. In other words, the tube12 may expand from a resting first diameter to an expanded seconddiameter when undergoing centrifugation. The float 20 may have a floatdiameter which is equal to or slightly larger than the first diameter ofthe tube 12 but which is less than the expanded second diameter of thetube 12. However, when the centrifugation is stopped, the inner diameterof the tube 12 may contract from its expanded second diameter back downto its first diameter to trap the float 20 in place at its equilibriumposition. The float 20 itself could alternatively be compressible undercentrifugally generated pressure but re-expand after centrifugation hasstopped so as to lock a position of the float 20 against the innersurface of the tube 12 at its equilibrium position, as illustrated inFIG. 1D.

As previously discussed, the float itself may also be in an alternativeshape. Another particular variation of the float may be seen in theperspective view of FIG. 2A which illustrates a tapered float 40 havinga tapered interface surface 42 formed in a conical configuration whichterminates in an apex 44 or in a convex configuration that may beatraumatically shaped, e.g., blunted, so as to minimize damage to theblood components. The tapered interface surface 42 may be optionallyshaped so as to mirror the tapered shape of the tube interior. Thetapered interface surface 42 may also prevent red blood cells fromaccumulating upon the upper surface of the float 40 duringcentrifugation. Additionally and/or alternatively, a bottom surface 42′of the float 40′, as shown in the side view of FIG. 2B, may also betapered as well so as to prevent platelets from depositing upon thelower surface as the red blood cells pack out, squeezing platelets outof the burgeoning pack.

In some embodiments, the degree of the slant may range anywhere from,e.g., about 2 to about 45 degrees, optionally from about 2 to about 40degrees, from about 2 to about 35 degrees, from about 2 to about 30degrees, from about 2 to about 25 degrees, from about 2 to about 20degrees, from about 2 to about 15 degrees, from about 2 to about 10degrees or from about 2 to about 5 degrees, relative to a normal surfaceof the float. In some embodiments, the degree of slant may rangeanywhere from, e.g., from about 2 to about 45 degrees, optionally fromabout 5 to about 40 degrees, from about 7.5 to about 35 degrees, fromabout 10 to about 30 degrees, from about 12.5 to about 25 degrees, orfrom about 15 to about 20 degrees, relative to a normal surface of thefloat. In other embodiments, the degree of the slant may be about 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,41, 42, 43, 44 or 45 degrees, relative to a normal surface of the float.

In some embodiments, the float has a surface topography configured tosubstantially prevent platelet adhesion. In other embodiments, the floatis configured to have a surface topography and surface tapered at anangle to substantially prevent platelet adhesion. The present inventorshave discovered the optimal relationship between surface topography andtaper angle.

In yet another variation, a syringe or container tube 50, as shown inthe perspective view of FIG. 3, may be used in a vacuum-drawn system forseparating and then collecting the supernatant fraction. The containertube 50 is shown with the separator float 72 contained within thechannel of the tube 50. The outer diameter 52 of the float 72 may beseen to form an annular channel, as described herein. A translatableplunger 54 may be slidably positioned within the channel and a pull rod58 may be coupled to the plunger 54 via a plunger lock 56 attached tothe plunger 54 on a side of the plunger 54 opposite to the float 72. Apull rod lock 60 may be integrated with the tube 50 at a distal surfaceof the tube 50 around a pull rod opening 62 through which the pull rod58 may be translated. A Luer assembly 64 may be integrated with at aproximal end of the tube 50 along with a valve 66 and a cap or septumLuer 68 which may be used to seal the Luer 64.

As discussed previously, a cap may be removable to provide access forwithdrawal while the use of a septum Luer 68 may enable the septum Luer68 to remain in place, e.g., for introducing blood into the tube 50.After centrifugation, the septum Luer 68 may be optionally removed toallow for connection to a withdrawal syringe. Additionally, use of aseptum Luer 68 may also obviate the use or need of a separate valve 66.

The proximal end of the tube 50 just below the Luer assembly 64 may alsodefine an interface surface 70 which may be tapered or shaped to receivethe float 72 in a corresponding manner to optimize the amount of the PRPlayer which may be withdrawn from the tube 50.

FIGS. 4A to 4G show side views of one variation for utilizing thecontainer tube 50. As shown in FIG. 4A, the pull rod 58 may be pushed tomove the plunger 54 and float 72 into an initial position where thefloat 72 is pushed into contact against the interface surface 70 of tube50 prior to receiving whole blood. The tube 50 may be supplied preloadedwith, e.g., anticoagulant or any other agent, contained within thechannel. Having the tube 50 preloaded with anticoagulant would enablethe blood to be drawn directly into the tube 50 without the need foradditional processing. With the valve 66 closed, the pull rod 58 may bepulled or pushed to move the plunger 54 into a distal position withinthe tube 50, as shown in FIG. 4B. The float 72 may be seen as droppingthrough the channel 74 of the tube 50 along with the plunger 54. Becausethe valve 66 is closed, a vacuum may be formed within the tube 50. Thepull rod 58 may be rotated partially about its longitudinal axisrelative to the tube 50 and plunger 54 so as to lock a position of thepull rod 58 to the tube 50 and to prevent the plunger 54 from beingmoved back proximally in position due to the vacuum.

A syringe or blood line may be attached to the Luer 64 and the valve 66may then be opened, as shown in FIG. 4C, allowing (whole) blood 76 to bedrawn through the Luer 64 and into the channel 74 by the vacuum formedwithin the tube 50. Once the blood 76 has filled the channel 74 of tube50, the valve 66 may then be closed again and the blood linedisconnected and removed. As shown in FIG. 4D, the pull rod 58 may bedecoupled or detached from the plunger lock 56 as well as from the pullrod lock 60 such that the pull rod 58 is fully removed so that the tube50, float 72, and whole blood 76 may be centrifuged. With the wholeblood 76 introduced within the channel 74 or tube 50, the float 72 mayremain settled at its distal position prior to centrifuging theassembly.

Once the tube 50 and its contents have been sufficiently centrifuged,the whole blood 76 may separate into its fractional components and thefloat 72 may alter its position within the channel 74 accordingly due tothe differing densities of the individual fractional layers. Thevariation shown in FIG. 4E illustrates the float 72 at equilibriumpositioned at the interface between a first layer, e.g., PRP layer 76′,and a second layer, e.g., RBC layer 76″. To effect removal of the PRPlayer 76′, a syringe or line 78 may be coupled to the Luer 64 and thevalve 66 may then be opened to allow withdrawal of the PRP layer 76′through line 78 and as shown in FIG. 4F. The RBC layer 76″ may remainbetween the plunger 54 and float 72 and the float 72 may remain at theinterface of the PRP layer 76′ and RBC layer 76″ as the PRP layer 76′ iswithdrawn through Luer 64. As shown, both the float 72 and plunger 54may accordingly move up through the channel 74. As the PRP layer 76′ isfully withdrawn, as shown in FIG. 4G, the upper surface of the float 72may come into contact against the interface surface 70 of the tube 50 sothat the float 72 and interface surface 70 form a float interface 80which may seal the tube 50 and prevent any further withdrawal throughLuer 64. The RBC layer 76″ may accordingly remain trapped between thelower surface of the float 72 and the plunger 54.

Due to the float 72 sealing against the RBC layer 76″, even if thewithdrawn PRP layer 76′ were reintroduced back into the tube 50, the RBClayer 76″ will remain contained beneath the float 72 and its volumeunchanged.

FIGS. 5A and 5B show another example of the resulting fractional layers76′, 76″ with the float 72 positioned at equilibrium between the layerscontained within the tube 50 after centrifugation. FIG. 5B shows syringe78 coupled to the Luer 64 and the PRP layer 76′ drawn into the syringe78 while the RBC layer 76″ remained trapped between the float 72 andplunger 54 within tube 50. Once the PRP layer 76′ has been sufficientlywithdrawn, the syringe 78 may be detached from Luer 64 for furtherprocessing and use leaving the RBC layer 76″ remaining in the tube 50.

As discussed herein, the whole blood 76 may be subjected to a “hardspin” to obtain a buffy coat above the midline 34 of the float oranywhere along the float. A volume of the resulting platelet-poor plasma(PPP) which may form above the PRP layer 76′ may be withdrawn from thetube 50. The buffy coat contained within the tube 50 may be re-suspendedin the smaller remaining volume by pulling the remaining supernatantfluid back-and-forth within the syringe 78 several times with minimalshearing or frothing. A stop may be removably affixed to the tube 50 sothat a distance between the float and the interface surface 70 of thetube 50 is fixed in order to define the volume of the supernatant fluidin which the buffy coat is resuspended to a preset amount. The buffycoat may then be re-suspended and withdrawn by removing the stop.

In yet another variation of a system that may be used to maintain thefloat 96 in a secured configuration particularly during shipping andhandling, FIG. 6 illustrates a perspective view of a tube assembly 90which enables the float 96 to be maintained in a secured configurationwhen the tube 92 may be filled with agents such as a volume ofanticoagulant, e.g., ACD-A. The tube 92 may be sealed under vacuum witha septum 94 and may allow for blood to be drawn directly from thepatient and into a tube 92 which may be preloaded with anticoagulant.The tube 92 may be fabricated from glass to prevent any potential issueswith foreign agents leaching from the tube and into the enclosed volumeof anticoagulant, e.g., during storage.

As shown, the float 96 may be enclosed within the tube 92 along with thevolume of anticoagulant. However, the float 96 may potentially risewithin the tube 92 due to density differences with the anticoagulant andthe float 96 is desirably secured into an immobile position for shippingand handling. In this variation, the float 96 may be fabricated from anynumber of biocompatible materials, such as HDPE, and may have a densityof, e.g., 1.03 to 1.07 or just under 1.04 in this variation. Because ofthe hardness of a glass tube 92, an external clamp may be inappropriatefor securing a position of the float 96 within the tube 92. If the tube92 were made from a plastic material, a clamp may be simply positionedover the external surface of the tube 92 in proximity to the float 96such that the walls of the tube 92 deform slightly and compress upon thefloat 96 to maintain it in position and prevent its movement (asdescribed in further detail below); however, applying a compressiveforce may not be feasible with a tube 92 made from a relatively hardermaterial such as glass. The float 96 may accordingly have an attractiveelement 98, such as a magnet, integrated within the float 96 such as adistal end or portion of the float 96 in proximity to the distal end orbottom of the tube 92 interior. The attractive element 98 may be variedin dimension (e.g., 3.175 mm length and 3.175 mm diameter) and magneticstrength depending on the desired attractive force to retain the float96 position.

The attractive element 98 may be embedded entirely within the float 96to prevent direct contact with any fluids within the tube 92 or it maybe configured to project beyond the surface of the float 96. Acorresponding external attractive element 102 (described below) may bepositioned along or against the exterior of the tube 92 in apposition tothe attractive element 98 contained within or along the float 96, e.g.,a removable external magnet positioned over the tube 92 or within oralong packaging containing the tube 92. Because the external attractiveelement 102 is positioned externally of the tube 92, the externalelement 102 may be simply removed a distance from the tube 92 to severthe magnetic attraction between the elements and thereby release theposition of the float 96 prior to or after receiving blood within thetube 92 so that the float 96 may be free to reposition itselfaccordingly within the tube 92.

FIG. 7A illustrates a perspective view of the tube 92 with the float 96positioned within the bottom of the tube interior with the attractiveelement 98 contained entirely within or along the float 96. FIG. 7Billustrates a perspective view of the float 96 removed from the tube 92to show how the attractive element 98 may be positioned near a distalend or portion of the float 96 while remaining entirely embedded within.

FIG. 8A shows a side view of the float 96 abutting against the bottom ofthe tube 92 with the attractive element 98 embedded within the float 96and in proximity to the bottom of the tube 92. The external attractiveelement 102 is illustrated as being positioned externally of the bottomof tube 92 and in proximity to the float 96 and attractive element 98such that the position of the float 96 is maintained securely within thetube 92. The bottom portion of the float 96 may be shaped with aninterface surface 100 which is configured to mate closely in acorresponding manner with the interior of the bottom of tube 92. FIG. 8Bshows another variation of the float 104 where the interface surface 108may be configured in a non-conforming shape such as a flattened profilewith the attractive element 106 embedded and still in proximity to theexternal attractive element 102, as shown.

In use, the external attractive element 102 may be removed to allow forthe float 96 to reposition itself during layer separation, as describedherein. FIG. 9 shows a perspective view of the released float 96repositioned to separate the layer of PPP 110 from RBC 112. Variationsof the float 96 having attractive element 98 embedded within areintended to be utilized in any number of combinations with any of thefloats described herein.

In yet another variation which may be used with or without theattractive elements embedded within the float, a removable packagingpost 120 may be incorporated within a cap 124, e.g., Luer cap, which maybe removably attached to the opening of the tube, as shown in the sideview of FIG. 10. The packaging post 120 may extend from the cap 124 andinto the interior of the tube and into contact against the top surfaceof the float 122 to maintain the position of the float 122 duringshipping and handling. When the tube is readied for use, the cap 124 andits extending packaging post 120 may be removed from the tube allowingfor the float 122 to move within the tube interior. While removing thepackaging post 120 may break a vacuum seal within the tube, thepackaging post 120 may be used with any of the float variationsdescribed herein.

In yet another variation for maintaining a position of the float 130during shipping and handling, the tube 92 may be fabricated from aplastic material and a clamp or other compressive mechanism having oneor more compressive members 132A, 132B may be simply positioned over theexternal surface of the tube 92 in proximity to the float 130, as shownin the perspective view of FIG. 11. The tube 92 may be vacuum sealedwith septum 94 (with or without any Luer fittings) enclosing the tube 92interior. The compressive members 132A, 132B of the clamp may be securedagainst the tube exterior to apply a compressive force 134 such that thewalls of the tube 92 deform slightly and compress upon the float 130 tomaintain it in position and prevent its movement prior to use.Compression of the float 130 may help to ensure that the float 130remains in position within the tube 92 particularly if any anticoagulantis preloaded within the tube 92. The clamp may be removed prior to useor after blood introduction and before centrifugation.

Statements of the Disclosure include:

Statement 1: An apparatus for separating blood, comprising: a tubedefining a channel and configured for receiving a quantity of blood; anda float contained within the tube and having a density which ispredefined so that the float is maintained at equilibrium between afirst layer formed from a first fractional component of the blood and asecond layer formed from a second fractional component of the blood.

Statement 2: The apparatus of Statement 1, wherein the float defines ashape selected from the group consisting of spherical, ellipsoidal, andcylindrical shapes.

Statement 3: The apparatus of Statement 1 or Statement 2, wherein thefloat defines at least one tapered or slanted surface.

Statement 4: The apparatus as in any of Statements 1-3, wherein thefloat defines at least one non-orthogonal surface relative to a normalsurface of the float.

Statement 5: The apparatus as in any of Statements 1-4, wherein thefloat has a density of 1.0 to 1.1 gram/ml.

Statement 6: The apparatus as in any of Statements 1-5, wherein thefloat has a density of 1.03 to 1.07 gram/ml.

Statement 7: The apparatus as in any of Statements 1-6, wherein thefloat has a density which is intermediate of the first layer comprisedof a RBC layer and the second layer comprised of a PRP layer.

Statement 8: The apparatus as in any of Statements 1-7, wherein an outerdiameter of the float is between 98 to 101% of the inner surface of thechannel.

Statement 9: The apparatus as in any of Statements 1-8, wherein thefloat has a surface configured to retain a layer of red blood cells.

Statement 10: The apparatus as in any of Statements 1-9 wherein thefloat has a surface configured to inhibit a layer of red blood cellsfrom adhering.

Statement 11: The apparatus as in any of Statements 1-10, furthercomprising an anticoagulant contained within the tube.

Statement 12: The apparatus as in any of Statements 1-11, wherein thedensity is further predefined to be maintained at equilibrium below athird layer formed from a third fractional component of the blood.

Statement 13: The apparatus as in any of Statements 1-12, wherein thedensity is further predefined to be maintained at equilibrium below asurface of a third layer formed from a third fractional component of theblood.

Statement 14: The apparatus of Statement 12 or Statement 13, wherein thethird layer comprised of a buffy coat layer.

Statement 15: The apparatus as in any of Statements 1-14, furthercomprising a septum sealing a proximal end of the tube.

Statement 16: The apparatus as in any of Statements 1-15, wherein thetube is configured to radially expand relative to its longitudinal axisfrom a first diameter to an expanded second diameter, the float having afloat diameter which is equal to or larger than the first diameter butsmaller the expanded second diameter.

Statement 17: The apparatus as in any of Statements 1-16, furthercomprising a first attractive element embedded within the float.

Statement 18: The apparatus of Statement 17, further comprising a secondattractive element positioned externally of the tube and in proximity tothe first attractive element.

Statement 19: The apparatus as in any of Statements 1-18, furthercomprising a clamp configured to apply a compressive force upon anexternal surface of the tube in proximity to the float to secure aposition of the float relative to the tube.

Statement 20: The apparatus as in any of Statements 1-19, furthercomprising a post which extends within an interior of the tube and intocontact against a top surface of the float to maintain a position of thefloat within the tube.

Statement 21: The apparatus of Statement 20, wherein the post isincorporated within a cap removably attachable to an opening of thetube.

Statement 22: The apparatus as in any of Statements 1-21, wherein thefloat has a density which is predefined so that a midline of the floatis maintained at equilibrium.

Statement 23: The apparatus as in any of Statements 1-22, wherein thefloat has a surface topography configured to substantially preventplatelet adhesion.

Statement 24: The apparatus as in any of Statements 1-23, wherein thefloat is configured to have a surface topography and surface tapered atan angle to substantially prevent platelet adhesion.

Statement 25: The apparatus as in any of Statements 1-24, wherein thefloat comprises a plurality of materials.

Statement 26: The apparatus as in any of Statements 1-25, wherein thefloat comprises a plurality of polymeric materials.

Statement 27: The apparatus as in Statement 26, wherein the floatcomprises a first polymeric material and a second polymeric material.

Statement 28: The apparatus as in Statement 26, wherein the firstpolymeric material and second polymeric material are present in a weightratio effective to provide a density of 1.0 to 1.1 gram/ml.

Statement 29: The apparatus as in Statement 27 or Statement 28, whereinthe first polymeric material and second polymeric material are presentin a weight ratio effective to provide a density of 1.03 to 1.07gram/ml.

Statement 30: The apparatus as in any of Statements 1-29, wherein thesize and shape of the float remain substantially fixed.

Statement 31: The apparatus as in any of Statements 1-30, wherein thefloat does not comprise a fluid-swellable material.

Statement 32. The apparatus as in any of Statements 1-31, wherein thefloat does not comprise any protrusions.

Statement 33: The apparatus as in any of Statements 1-32, wherein thefloat has a surface topography and shape that substantially avoidsdamage to one or more platelets.

Statement 34: The apparatus as in any of Statements 1-33, wherein thefloat has a surface topography and shape that prevents damaging one ormore platelets.

Statement 35: The apparatus as in any of Statements 9-34, wherein thelayer of red blood cells has a thickness effective to substantiallyavoid damaging one or more platelets.

Statement 36: A method for separating blood, comprising: introducing avolume of blood into a channel of a tube which encloses a float having adensity which is predefined; subjecting the tube to a centrifugationsuch that the blood separates into at least a first layer formed from afirst fractional component of the blood and a second layer formed from asecond fractional component of the blood, wherein the float ismaintained at equilibrium between the first layer and the second layer.

Statement 37: The method of Statement 36, wherein the float defines ashape selected from the group consisting of spherical, ellipsoidal, andcylindrical shapes.

Statement 38: The method as in any of Statements 36-37, wherein thefloat defines at least one tapered or slanted surface.

Statement 39: The method as in any of Statements 36-38, wherein thefloat has a density of 1.0 to 1.1 gram/ml.

Statement 40: The method as in any of Statements 36-39, wherein thefloat has a density of 1.03 to 1.07 gram/ml.

Statement 41: The method as in any of Statements 36-40, wherein thefloat has a density which is intermediate of the first layer comprisedof a RBC layer and the second layer comprised of a PRP layer.

Statement 42: The method as in any of Statements 36-41, wherein an outerdiameter of the float is between 98 to 101% of the inner surface of thechannel.

Statement 43: The method as in any of Statements 36-42, whereinsubjecting the tube to a centrifugation further comprises retaining alayer of red blood cells upon a surface of the float.

Statement 44: The method as in any of Statements 36-43, whereinsubjecting the tube to a centrifugation further comprises inhibitingadhesion of a layer of red blood cells upon a surface of the float.

Statement 45: The method as in any of Statements 36-44, furthercomprising introducing an anticoagulant within the tube.

Statement 46: The method as in any of Statements 36-45, furthercomprising subjecting the tube to a second centrifugation such that theblood further separates into a third layer formed from a buffy coatlayer.

Statement 47: The method as in Statement 46 wherein the density of thefloat is further predefined to be maintained at equilibrium below thethird layer.

Statement 48: The method as in any of Statements 46-47, furthercomprising removing a post extending within an interior of the tubewhich is vacuum sealed and into contact against a top surface of thefloat prior to introducing the volume of blood.

Statement 49: The method as in Statement 48, further comprising breakinga vacuum seal within the tube while removing the post from within theinterior of the tube.

Statement 50: The method as in any of Statements 46-49, whereinsubjecting the tube to a centrifugation comprises radially expanding thetube relative to its longitudinal axis from a first diameter to anexpanded second diameter such that the float is free to migrate withinthe channel.

Statement 51: The method of Statement 50, further comprising stoppingthe centrifugation such that tube contracts from its expanded seconddiameter back to its first diameter and secures the float at itsequilibrium position against the channel.

Statement 52: The method as in any of Statements 46-51, furthercomprising securing a position of the float within the tube via a firstattractive element embedded within the float and a second attractiveelement positioned externally of the tube and in proximity to the firstattractive element prior to subjecting the tube to the centrifugation.

Statement 53: The method as in any of Statements 46-51, furthercomprising securing a position of the float within the tube via a clampconfigured to apply a compressive force upon an external surface of thetube in proximity to the float.

Statement 54: The method as in any of Statement s 36-52, wherein amidline of the float is maintained at equilibrium.

Statement 55: A method for preparing a platelet rich plasma, comprising:providing an apparatus as in any of Statements 1-35 and a blood sample(e.g. whole blood); centrifuging the blood sample in the apparatus for atime and at a speed sufficient to separate the blood sample into a firstphase and a second phase, wherein the first phase comprises red bloodcells and the second phase comprises plasma; and removing a portion ofthe second phase to create a platelet rich plasma.

Statement 56: The method as in Statement 55, wherein the portion removedfrom the second phase comprises platelet poor plasma.

Statement 57: The method as in Statements 55-56, further comprisingresuspending the platelet rich plasma.

Statement 58: The method as in Statements 55-57, wherein the float ismaintained at equilibrium between the first phase and the second phase.

Statement 59: The method as in Statements 55-58, wherein the apparatusis centrifuged for a time and at a speed sufficient to separate theblood sample into a first phase, a second phase and a third phase.

Statement 60: A method for separating a biological sample, comprising:introducing a volume of blood into the apparatus as in any of Statements1-36; subjecting the apparatus to a centrifugation such that thebiological sample separates into a first phase and a second phase;wherein the float is maintained at equilibrium between the first phaseand the second phase.

Statement 61: A method for separating blood, comprising: introducing avolume of blood into the apparatus as in any of Statements 1-36;subjecting the apparatus to a centrifugation such that the bloodseparates into at least a first layer formed from a first fractionalcomponent of the blood and a second layer formed from a secondfractional component of the blood; wherein the float is maintained atequilibrium between the first layer and the second layer.

Statement 62: A method for treating, preventing or ameliorating asymptom associated with: acne; alopecia; pain; periodontal disease;periodontal defects; a chronic wound; diabetic foot ulcer; traumaticinjury; scars; incontinence; and/or wrinkles, comprising administering aproduct produced by the method as in any of Statements 55-61, to amammalian subject in need thereof.

Statement 63: A method for treating, preventing or ameliorating asymptom associated with: acne; alopecia; pain; periodontal disease;periodontal defects; a chronic wound; diabetic foot ulcer; traumaticinjury; scars; incontinence; and/or wrinkles, comprising administering aproduct produced by any one of the methods described herein to amammalian subject in need thereof.

Statement 64: A method for increasing, enhancing or promoting: hairgrowth; tissue healing; tissue regeneration; sexual wellness; bonegrowth; bone regeneration; and/or periodontal regeneration; comprisingadministering a product produced by the method as in any of Statements55-61, to a mammalian subject in need thereof.

Statement 65: A method for increasing, enhancing or promoting: hairgrowth; tissue healing; tissue regeneration; sexual wellness; bonegrowth; bone regeneration; and/or periodontal regeneration; comprisingadministering a product produced by any one of the methods describedherein to a mammalian subject in need thereof.

Statement 66: A composition comprising a product produced by the methodas in any of Statements 55-61; and a cosmetically acceptable carrier.

Statement 67: A composition comprising a product produced by any one ofthe methods described herein; and a cosmetically acceptable carrier.

Statement 68: A pharmaceutical composition comprising a product producedby the method as in any of Statements 55-61; and a pharmaceuticallyacceptable carrier.

Statement 69: A pharmaceutical composition comprising a product producedby any one of the methods described herein; and a pharmaceuticallyacceptable carrier.

EXAMPLES

In one example utilizing the devices and methods described, samples ofhuman blood were collected into tubes filled with an anticoagulant(ACD-A). Each of the tubes were spun at 3200 rpm (1500×g) for a periodof 5 minutes in a swinging bucket centrifuge. The float contained withinthe collection tubes had a predefined density of 1.04 g/ml.

After spinning the blood samples into their constituent components, thecollection tubes were inverted several times to resuspend the plateletsand the harvested upper fractional layers. The volume of the whole bloodintroduced into the tubes, the volume of the PRP harvested, the relativebaseline counts, and the fold increase and percentage recovered wererecorded and calculated, as presented in the following TABLE 1.

TABLE 1 FOLD INCREASE/PERCENTAGE RECOVERY FROM BLOOD SAMPLES Whole SpinSpin Fixed/ Blood PRP Baseline PRP Time Speed Spin Swing Vol. IN Vol.OUT Ct. Ct. Fold % (min) (rpm) xg Bucket (ml) (ml) (×10e6) (×10e6)Increase Recovery 5 3200 1500 Swing 10 5.8 124 206 1.66 96.35 5 32001500 Swing 10 6 124 154 1.24 74.52

As shown in TABLE 1 above, the use of the float having the predefineddensity of 1.04 g/ml proved to be effective in separating the componentlayers from whole blood for harvesting from the collection tubes.

The apparatus and methods disclosed above are not limited to theindividual embodiments which are shown or described but may includecombinations which incorporate individual features between the differentvariations. Modification of the above-described assemblies and methodsfor carrying out the invention, combinations between differentvariations as practicable, and variations of aspects of the inventionthat are obvious to those of skill in the art are intended to be withinthe scope of the claims.

What is claimed is:
 1. An apparatus for separating blood, comprising: atube defining a channel and configured for receiving a quantity ofblood; a float contained within the tube and having a density which ispredefined so that the float is maintained at equilibrium between afirst layer formed from a first fractional component of the blood and asecond layer formed from a second fractional component of the blood,wherein the channel defined by the tube is maintained under vacuum priorto receiving the quantity of blood wherein the float remains settled ina distal position within the tube under vacuum.
 2. The apparatus ofclaim 1 wherein the float defines a shape selected from the groupconsisting of spherical, ellipsoidal, and cylindrical shapes.
 3. Theapparatus of claim 1 wherein the float defines at least one tapered orslanted surface.
 4. The apparatus of claim 1 wherein the float has adensity of 1.0 to 1.1 gram/ml.
 5. The apparatus of claim 1 wherein thefloat has a density of 1.03 to 1.07 gram/ml.
 6. The apparatus of claim 1wherein the float has a density which is intermediate of the first layercomprised of a RBC layer and the second layer comprised of a PRP layer.7. The apparatus of claim 1 wherein an outer diameter of the float whichcontacts an inner surface of the channel is between 98 to 101% of theinner diameter of the channel.
 8. The apparatus of claim 1 wherein thefloat has a non-orthogonal surface configured to retain a layer of redblood cells.
 9. The apparatus of claim 1 wherein the float has asmoothed or tapered surface configured to inhibit a layer of red bloodcells from adhering.
 10. The apparatus of claim 1 further comprising ananticoagulant contained within the tube.
 11. The apparatus of claim 1wherein the density is further predefined to be maintained atequilibrium below a third layer formed from a third fractional componentof the blood.
 12. The apparatus of claim 1 wherein the density isfurther predefined to be maintained at equilibrium below a surface of athird layer formed from a third fractional component of the blood. 13.The apparatus of claim 12 wherein the third layer comprised of a buffycoat layer.
 14. The apparatus of claim 1 further comprising a septumsealing a proximal end of the tube.
 15. The apparatus of claim 1 whereinthe tube is configured to radially expand relative to its longitudinalaxis from a first diameter to an expanded second diameter, the floathaving a float diameter which is equal to or larger than the firstdiameter but smaller the expanded second diameter.
 16. The apparatus ofclaim 1 wherein the float has a density which is predefined so that amidline of the float is maintained at equilibrium.
 17. The apparatus ofclaim 1 wherein the float has a surface topography configured to preventplatelet adhesion.
 18. The apparatus of claim 1 wherein the float isconfigured to have a surface topography and surface tapered at an angleto prevent platelet adhesion.
 19. The apparatus of claim 1 wherein thefloat comprises a plurality of materials.
 20. The apparatus of claim 1wherein the float comprises a plurality of polymeric materials.
 21. Theapparatus of claim 20 wherein the float comprises a first polymericmaterial and a second polymeric material.
 22. The apparatus of claim 21wherein the first polymeric material and second polymeric material arepresent in a weight ratio effective to provide a density of 1.0 to 1.1gram/ml.
 23. The apparatus of claim 21 wherein the first polymericmaterial and second polymeric material are present in a weight ratioeffective to provide a density of 1.03 to 1.07 gram/ml.
 24. Theapparatus of claim 1 wherein the size and shape of the float remainfixed.
 25. The apparatus of claim 1 wherein the float does not comprisea swellable material.
 26. The apparatus of claim 1 wherein the floatdoes not comprise any protrusions.
 27. The apparatus of claim 1 whereinthe float has a surface topography and shape that avoids damage to oneor more platelets.